[V4,2/2] PCI/portdrv: Add #defines for the AER and DPC Interrupt Message Number masks

Message ID 1507719178-112556-3-git-send-email-liudongdong3@huawei.com
State Superseded
Headers show
Series
  • PCI/portdrv: Fix MSI/MSI-X bug for PCIe port service drivers
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Commit Message

Dongdong Liu Oct. 11, 2017, 10:52 a.m.
In the AER case, the mask isn't strictly necessary because there are no
higher-order bits above the Interrupt Message Number, but using a #define
will make it possible to grep for it.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
 drivers/pci/pcie/portdrv_core.c | 4 ++--
 include/uapi/linux/pci_regs.h   | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

Comments

David Laight Oct. 11, 2017, 1:01 p.m. | #1
From: Dongdong Liu
> Sent: 11 October 2017 11:53
> In the AER case, the mask isn't strictly necessary because there are no
> higher-order bits above the Interrupt Message Number, but using a #define
> will make it possible to grep for it.
> 
> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
> ---
>  drivers/pci/pcie/portdrv_core.c | 4 ++--
>  include/uapi/linux/pci_regs.h   | 2 ++
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 9692379..2b48297 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -116,7 +116,7 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
>  		 */
>  		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
>  		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
> -		entry = reg32 >> 27;
> +		entry = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;

You've still got the hard coded 27 - which is almost more important than the mask.
Perhaps define things so this is:
		entry = PCI_ERR_ROOT_AER_IRQ(reg32);

Think I'd shift then mask with 0x1f.

	David
Bjorn Helgaas Oct. 11, 2017, 1:34 p.m. | #2
On Wed, Oct 11, 2017 at 01:01:26PM +0000, David Laight wrote:
> From: Dongdong Liu
> > Sent: 11 October 2017 11:53
> > In the AER case, the mask isn't strictly necessary because there are no
> > higher-order bits above the Interrupt Message Number, but using a #define
> > will make it possible to grep for it.
> > 
> > Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> > Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
> > ---
> >  drivers/pci/pcie/portdrv_core.c | 4 ++--
> >  include/uapi/linux/pci_regs.h   | 2 ++
> >  2 files changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> > index 9692379..2b48297 100644
> > --- a/drivers/pci/pcie/portdrv_core.c
> > +++ b/drivers/pci/pcie/portdrv_core.c
> > @@ -116,7 +116,7 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
> >  		 */
> >  		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> >  		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
> > -		entry = reg32 >> 27;
> > +		entry = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
> 
> You've still got the hard coded 27 - which is almost more important than the mask.
> Perhaps define things so this is:
> 		entry = PCI_ERR_ROOT_AER_IRQ(reg32);
> 
> Think I'd shift then mask with 0x1f.

Personally, I prefer to have the mask unshifted so it's easy to see
where the fields are in the register and to compare them with the
spec, e.g.,

  #define  PCI_EXP_DEVCAP_PAYLOAD 0x00000007 /* Max_Payload_Size */
  #define  PCI_EXP_DEVCAP_PHANTOM 0x00000018 /* Phantom functions */
  #define  PCI_EXP_DEVCAP_EXT_TAG 0x00000020 /* Extended tags */

Should there be a #define for the shift?  Maybe.  It doesn't bother me
unless it's used in many places.  Here I think there'd only be one
use, so having it hard-coded along with the symbolic mask is enough
for me.  Sometimes too many #defines clutter up the include file.

Just my personal preferences.

Bjorn

Patch

diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 9692379..2b48297 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -116,7 +116,7 @@  static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 		 */
 		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
 		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
-		entry = reg32 >> 27;
+		entry = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
 		if (entry >= nr_entries)
 			goto out_free_irqs;
 
@@ -142,7 +142,7 @@  static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 		 */
 		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
 		pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP, &reg16);
-		entry = reg16 & 0x1f;
+		entry = reg16 & PCI_EXP_DPC_IRQ;
 		if (entry >= nr_entries)
 			goto out_free_irqs;
 
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index f8d5804..756e704 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -746,6 +746,7 @@ 
 #define PCI_ERR_ROOT_FIRST_FATAL	0x00000010 /* First UNC is Fatal */
 #define PCI_ERR_ROOT_NONFATAL_RCV	0x00000020 /* Non-Fatal Received */
 #define PCI_ERR_ROOT_FATAL_RCV		0x00000040 /* Fatal Received */
+#define PCI_ERR_ROOT_AER_IRQ		0xf8000000 /* Advanced Error Interrupt Message Number */
 #define PCI_ERR_ROOT_ERR_SRC	52	/* Error Source Identification */
 
 /* Virtual Channel */
@@ -960,6 +961,7 @@ 
 
 /* Downstream Port Containment */
 #define PCI_EXP_DPC_CAP			4	/* DPC Capability */
+#define PCI_EXP_DPC_IRQ			0x1f	/* DPC Interrupt message number */
 #define  PCI_EXP_DPC_CAP_RP_EXT		0x20	/* Root Port Extensions for DPC */
 #define  PCI_EXP_DPC_CAP_POISONED_TLP	0x40	/* Poisoned TLP Egress Blocking Supported */
 #define  PCI_EXP_DPC_CAP_SW_TRIGGER	0x80	/* Software Triggering Supported */